Advection Fan and A Fan Frame Thereof

ABSTRACT

An advection fan includes a fan frame, an impeller and a cover plate. The fan frame has a bottom plate and a lateral wall. A shaft seat is arranged on the bottom plate. The lateral wall surrounds the shaft seat and has an inner peripheral face. The lateral wall includes first and second air-guiding portions. An air inlet and an air outlet are formed between the first and second air-guiding portions. The first air-guiding portion includes a first guiding face intersecting the inner peripheral face by a first included angle, which is smaller than 180 degrees. The second air-guiding portion includes a second guiding face. A distance between the first and second guiding faces is gradually reduced from the air inlet towards the center of the fan frame. The impeller is rotatably coupled with the shaft seat. The cover plate is coupled with the lateral wall.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an advection fan and a fan frame thereof and, more particularly, to an advection fan that draws and expels air in the radial direction, as well as a fan frame adapted to receive the advection fan.

2. Description of the Related Art

FIGS. 1 and 2 show a conventional advection fan 9, which includes a frame 91, an impeller 92 and a cover plate 93. The frame 91 includes a bottom plate 911 on which a shaft seat 912 is mounted. The frame 91 has an air inlet 913 and an air outlet 914 on two adjoined sides of the frame 91, with the inlet 913 and the air outlet 914 separated from each other by an air-guiding portion 915. The frame 91 further includes a lateral wall 916. The inlet 913 is formed between the air-guiding portion 915 and one end of the lateral wall 916, the air outlet 914 is formed between the air-guiding portion 915 and the other end of the lateral wall 916. The impeller 92 is rotatably mounted on the shaft seat 912. The cover plate 93 is mounted on the frame 91. Preferably, the cover plate 93 is coupled with the top edge of the frame 91 via a plurality of fixing members 94. In this arrangement, the impeller 92 may rotate to draw air via the inlet 913 and to expel air via the air outlet 914.

The lateral wall 916 has an inner face extending across the bottom plate 911 from the inlet 913 to the air outlet 914. However, since the inner face of the lateral wall 916 extends perpendicularly to the inlet 913, the inner face of the lateral wall 916 will not smoothly guide the air into the frame 91. In this regard, when the impeller 92 rotates to draw air via the air inlet 913, the air entering the frame 91 cannot be concentrated, resulting in squeezing of air inside the frame 91. As a result, turbulences are caused. In this situation, a portion of air will undesirably retain in the frame 91, affecting the air circulation of the advection fan 9. Thus, the air volume of the air inlet 913 is reduced. The air volume of the air outlet 914 is even reduced. Disadvantageously, the performance of the advection fan 9 is not improved.

SUMMARY OF THE INVENTION

It is therefore the objective of this invention to provide an advection fan and a fan frame adapted to receive the advection fan. In the advection fan, air will be concentrated and guided into the fan frame by arranging first and second guiding faces at an air inlet wherein the distance between the first and second guiding faces is gradually reduced from the air inlet towards the center of the fan frame. Thus, the air volume of the advection fan is increased.

One embodiment of the invention discloses an advection fan including a fan frame, an impeller and a cover plate. The fan frame has a bottom plate and a lateral wall. A shaft seat is arranged on the bottom plate. The lateral wall surrounds the shaft seat and has an inner peripheral face facing the shaft seat. The lateral wall includes a first air-guiding portion and a second air-guiding portion. The first air-guiding portion has first and second ends. The second air-guiding portion has first and second ends. An air inlet is formed between the first ends of the first and second air-guiding portions. An air outlet is formed between the second ends of the first and second air-guiding portions. The first air-guiding portion includes a first guiding face at the air inlet. The second air-guiding portion includes a second guiding face at the air inlet. The first guiding face intersects the inner peripheral face of the lateral wall by a first included angle, which is smaller than 180 degrees. A distance between the first and second guiding faces is gradually reduced from the air inlet towards a center of the fan frame. The impeller is rotatably coupled with the shaft seat of the fan frame. The cover plate is coupled with a top edge of the lateral wall.

In a preferred form shown, a second included angle is presented between the second guiding face and the inner peripheral face of the lateral wall. The second included angle is smaller than 180 degrees.

In the preferred form shown, the first air-guiding portion comprises a first air-guiding face at the air outlet, and the second air-guiding portion comprises a second air-guiding face at the air outlet.

In the preferred form shown, the first and second air-guiding faces are parallel to each other.

In the preferred form shown, a distance between the first and second air-guiding faces is gradually reduced from the air outlet towards the center of the fan frame.

In the preferred form shown, the first air-guiding portion has a first angular end at the air inlet, the first air-guiding portion has a second angular end at the air outlet. The second air-guiding portion has a third angular end at the air inlet. The second air-guiding portion has a fourth angular end at the air outlet. A first boundary line extends through the first angular end of the first air-guiding portion and the third angular end of the second air-guiding portion. A second boundary line extends through the second angular end of the first air-guiding portion and the fourth angular end of the second air-guiding portion. A reference line extends through the center of the shaft seat and the air outlet. The reference line extends perpendicular to the second boundary line. The lateral wall further comprises an air-separating portion, which is coupled with the second air-guiding portion and extends inwards in the radial direction of the fan. The air-separating portion is located between the reference line and the first boundary line.

In the preferred form shown, a first auxiliary line extends through the center of the shaft seat and the first angular end of the first air-guiding portion, the first auxiliary line intersects the reference line by a third included angle.

In the preferred form shown, the third included angle is between 35 degrees and 55 degrees.

In the preferred form shown, the third included angle is 35 degrees.

In the preferred form shown, the third included angle is 45 degrees.

In the preferred form shown, the third included angle is 55 degrees.

In the preferred form shown, a second auxiliary line extends through the center of the shaft seat and the fourth angular end of the second air-guiding portion, the second auxiliary line intersects the reference line by a fourth included angle.

In the preferred form shown, the fourth included angle is between 15 degrees and 35 degrees.

In the preferred form shown, the fourth included angle is 15 degrees.

In the preferred form shown, the fourth included angle is 25 degrees.

In the preferred form shown, the fourth included angle is 35 degrees.

The other embodiment of the invention discloses a fan frame of an advection fan, which includes a bottom plate and a lateral wall. A shaft seat is arranged on the bottom plate. The lateral wall surrounds the shaft seat and has an inner peripheral face facing the shaft seat. The lateral wall includes a first air-guiding portion and a second air-guiding portion. The first air-guiding portion has first and second ends. The second air-guiding portion has first and second ends. An air inlet is formed between the first ends of the first and second air-guiding portions. An air outlet is formed between the second ends of the first and second air-guiding portions. The first air-guiding portion includes a first guiding face at the air inlet. The second air-guiding portion includes a second guiding face at the air inlet. The first guiding face intersects the inner peripheral face of the lateral wall by a first included angle, which is smaller than 180 degrees. A distance between the first and second guiding faces is gradually reduced from the air inlet towards a center of the fan frame. The impeller is rotatably coupled with the shaft seat of the fan frame. The cover plate is coupled with a top edge of the lateral wall.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1 is an exploded view of a conventional advection fan.

FIG. 2 is a top view of the conventional advection fan.

FIG. 3 is an exploded view of an advection fan according to a preferred embodiment of the invention.

FIG. 4 a is a top view of the advection fan of the invention.

FIG. 4 b is another top view of the advection fan of the invention.

FIG. 5 shows the relations of air volume verse air pressure of the conventional advection fan and the advection fan of the invention when the third included angle is in 35, 45 and 55 degrees.

FIG. 6 shows the relations of air volume verse air pressure of the conventional advection fan and the advection fan of the invention when the fourth included angle is in 15, 25 and 35 degrees.

In the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the terms “first”, “second”, “third”, “fourth”, “inner”, “outer” “top”, “bottom” and similar terms are used hereinafter, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings, and are utilized only to facilitate describing the invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 3 shows an advection fan according to a preferred embodiment of the invention. The advection fan includes a fan frame 1, an impeller 2 and a cover plate 3. The impeller 2 is installed in the fan frame 1 and between the fan frame 1 and the cover plate 3 for driving air. The cover plate 3 is coupled with the fan frame 1.

The fan frame 1 has a bottom plate 11 and a lateral wall 12. A shaft seat 111 is arranged on one face of the bottom plate 11. The lateral wall 12 is formed on the face of the bottom plate 11 that is provided with the shaft seat 111. The lateral wall 12 surrounds the shaft seat 111 and has an inner peripheral face 121 facing the shaft seat 111. The inner peripheral face 121 may extend in an arcuate manner corresponding to the outline of the impeller 2, so as to guide the incoming air along the inner peripheral face 121.

The lateral wall 12 includes a first air-guiding portion 122 and a second air-guiding portion 123. The first air-guiding portion 122 has first and second ends. The second air-guiding portion 123 has first and second ends. An air inlet 13 is formed between the first ends of the first air-guiding portion 122 and the second air-guiding portion 123. An air outlet 14 is formed between the second ends of the first air-guiding portion 122 and the second air-guiding portion 123. Air can be drawn into the advection fan via the air inlet 13 and be expelled from the advection fan via the air outlet 14. The bottom plate 11 may be of any shape such as a rectangular shape, a circular shape or an irregular shape. In this embodiment, the bottom plate 11 is in the rectangular shape wherein the air inlet 13 and the air outlet 14 are located on two adjoined sides of the bottom plate 11. The first air-guiding portion 122 includes a first guiding face 1221 at the air inlet 13, as well as a first air-guiding face 1222 at the air outlet 14. The second air-guiding portion 123 includes a second guiding face 1231 at the air inlet 13, as well as a second air-guiding face 1232 at the air outlet 14. The first air-guiding portion 122 may further include an air-separating portion 124, which is coupled with the second air-guiding portion 123 and extends inwards in the radial direction of the fan. The air-separating portion 124 does separate the incoming air from the exiting air, preventing turbulences from forming due to interference between the incoming air and the exiting air.

Referring to FIG. 4 a, the first guiding face 1221 intersects the inner peripheral face 121 by a first included angle α₁. The first included angle α₁ is smaller than 180 degrees. Similarly, a second included angle α₂ is presented between the second guiding face 1231 and the inner peripheral face 121. The second included angle α₂ is smaller than 180 degrees. The air-separating portion 124 has an end face facing the shaft seat 111, which is the part of the inner peripheral face 121 located at the second air-guiding portion 123.

The distance between the first guiding face 1221 and the second guiding face 1231 is gradually reduced from the air inlet 13 towards the center of the fan frame 1. Specifically, referring to FIG. 4 b, a reference line R may extend perpendicular to the air inlet 13 from the shaft seat 111. The first guiding face 1221 has a first edge that is relatively close to the shaft seat 111 and a second edge that is relatively distant to the shaft seat 111. The first edge is spaced from the reference line R at a first distance along a direction perpendicular to the reference line R, and the second edge is spaced from the reference line R at a second distance along the direction perpendicular to the reference line R. The first distance is smaller than the second distance. Similarly, the second guiding face 1231 has a third edge that is relatively close to the shaft seat 111 and a fourth edge that is relatively distant to the shaft seat 111. The third edge is spaced from the reference line R at a third distance along the direction perpendicular to the reference line R, and the fourth edge is spaced from the reference line R at a fourth distance along the direction perpendicular to the reference line R. The third distance is smaller than the fourth distance. Briefly speaking, the first guiding face 1221 and the second guiding face 1231 resemble the shape of “/ \” when viewing from the right side of the fan frame 1 in FIG. 4 a. This efficiently guides the air into the fan frame 1. The first air-guiding face 1222 may be parallel to the second air-guiding face 1232. Alternatively, the distance between the first air-guiding face 1222 and the second air-guiding face 1232 may be gradually reduced from the air outlet 14 to the center of the fan frame 1. In this case, the first air-guiding face 1222 and the second air-guiding face 1232 resemble the shape of “/ \”, guiding the air out of the fan frame 1 in a smooth manner.

Based on this, the first air-guiding portion 122 has a first angular end 1223 at the air inlet 13, as well as a second angular end 1224 at the air outlet 14. The second air-guiding portion 123 has a third angular end 1233 at the air inlet 13, as well as a fourth angular end 1234 at the air outlet 14.

A first boundary line B1 extends through the first angular end 1223 of the first air-guiding portion 122 and the third angular end 1233 of the second air-guiding portion 123. A second boundary line B2 extends through the second angular end 1224 of the first air-guiding portion 122 and the fourth angular end 1234 of the second air-guiding portion 123. A reference line S0 extends through the center of the shaft seat 111 and the air outlet 14, and extends parallel to the second boundary line B2. In the embodiment, the air-separating portion 124 may be optionally arranged between the reference line S0 and the first boundary line B1. In addition, the face of the air outlet 14 that faces the air outlet 14 may be, but not limited to be, coplanar with the second air-guiding portion 123.

In this embodiment, the fan frame 1 may further define a first auxiliary line S1 extending through the center of the shaft seat 111 and the first angular end 1223 of the first air-guiding portion 122, as well as a second auxiliary line S2 extending through the center of the shaft seat 111 and the fourth angular end 1234 of the second air-guiding portion 123. The first auxiliary line S1 may intersect the reference line S0 by a third included angle θ₁ which is preferably between 35 degrees to 55 degrees. The first guiding face 1221 is located within the third included angle θ₁. The second auxiliary line S2 may intersect the reference line S0 by a fourth included angle θ₂, which is preferably between 15 degrees to 35 degrees. The second air-guiding face 1232 is located within the fourth included angle θ₂.

The impeller 2 may be rotatably coupled with the shaft seat 111 of the fan frame 1. A motor may be provided to drive the impeller 2 to rotate, so that the impeller 2 will draw air via the air inlet 13 and expel air via the air outlet 14. The principle of the motor driving the impeller 2 can be readily appreciated by one skilled in the art, so it is not described herein again.

The cover plate 3 is coupled with the fan frame 1 over the impeller 2. The cover plate 3 may be coupled with the top edge of the lateral wall 12 via a plurality of fixing members 4.

Based on the above structures, since the distance between the first guiding face 1221 and the second guiding face 1231 is gradually reduced from the air inlet 13 towards the center of the fan frame 1, the air entering the fan frame 1 can be efficiently concentrated. Advantageously, the incoming air can be smoothly guided to the air outlet 14 without disruption to the flow of the air, preventing turbulences from forming due to the squeezing of air inside the fan frame 1. Therefore, air can be guided through the air inlet 13 and the air outlet 14 more smoothly.

Further, when the first air-guiding face 1222 and the second air-guiding face 1232 are parallel to each other or when the space between the first air-guiding face 1222 and the second air-guiding face 1232 is gradually reduced from the air outlet 14 to the center of the fan frame 1, the air can be smoothly guided out of the fan frame 1. Therefore, the air volume of the air outlet 14 will be increased. In this arrangement, it can even prevent the expelled air from being drawn back into the fan frame 1 by the impeller 2, increasing the air volume of the air inlet 13 and the air outlet 14.

FIG. 5 shows the relation of air volume verse air pressure of the conventional advection fan when the impeller rotates in a speed of 4000 rpm, as well as the relations of air volume verse air pressure of the advection fan of the invention when the impeller 2 rotates in the speed of 4000 rpm based on different third included angles θ₁. In FIG. 5, line L0 represents the relation between air volume and air pressure of the conventional advection fan. Further, line L1 represents the relation between air volume and air pressure of the advection fan of the invention when the third included angle θ₁ is 35 degrees, line L2 represents the relation between air volume and air pressure of the advection fan when the third included angle θ₁ is 45 degrees, and line L3 represents the relation between air volume and air pressure of the advection fan when the third included angle θ₁ is 55 degrees. It can be observed in FIG. 5 that the advection fan of the invention has an improved performance over the conventional one. It can also be observed in FIG. 5 that the advection fan of the invention has substantially the same performance when the third included angle θ₁ is 35, 45 and 55 degrees. Thus, it can be concluded that the advection fan of the invention provides satisfactory performance when the third included angle θ₁ is 35, 45 and 55.

FIG. 6 shows the relation of air volume verse air pressure of the conventional advection fan when the impeller rotates in the speed of 4000 rpm, as well as the relations of air volume verse air pressure of the advection fan of the invention when the impeller 2 rotates in the speed of 4000 rpm based on different fourth included angles θ₂. In FIG. 6, line L0 represents the relation between air volume and air pressure of the conventional advection fan, as described previously. Further, line L4 represents the relation between air volume and air pressure of the advection fan of the invention when the fourth included angle θ₂ is 15 degrees, line L2 represents the relation between air volume and air pressure of the advection fan when the fourth included angle θ₂ is 25 degrees, and line L3 represents the relation between air volume and air pressure of the advection fan when the fourth included angle θ₂ is 35 degrees. It can be observed in FIG. 6 that the advection fan of the invention has an improved performance over the conventional one. It can also be observed in FIG. 6 that the advection fan of the invention has substantially the same performance when the fourth included angle θ₂ is 15 and 25 degrees. The advection fan of the invention has slightly better performance when the fourth included angle θ₂ is 15 and 25 degrees than it does when the fourth included angle θ₂ is 35 degrees. Thus, it can be concluded that the advection fan of the invention provides satisfactory performance when the fourth included angle θ₂ is between 15 degrees and 35 degrees.

In summary, the advection fans of the preferred embodiments are capable of smoothly guiding air through the air inlet 13 and the air outlet 14 by arranging the first guiding face 1221 and the second guiding face 1231 wherein the distance between the first guiding face 1221 and the second guiding face 1231 is gradually reduced from the air inlet 13 towards the center of the fan frame 1. Thus, the air volume of the air inlet 13 and the air outlet 14 can be increased, thereby improving the performance of the advection fan.

Although the invention has been described in detail with reference to its presently preferable embodiments, it will be understood by one of ordinary skill in the art that various modifications can be made without departing from the spirit and the scope of the invention, as set forth in the appended claims. 

What is claimed is:
 1. An advection fan comprising: a fan frame having a bottom plate and a lateral wall, wherein a shaft seat is arranged on the bottom plate, wherein the lateral wall surrounds the shaft seat and has an inner peripheral face facing the shaft seat, wherein the lateral wall includes a first air-guiding portion and a second air-guiding portion, wherein the first air-guiding portion has first and second ends, wherein the second air-guiding portion has first and second ends, wherein an air inlet is formed between the first ends of the first and second air-guiding portions, wherein an air outlet is formed between the second ends of the first and second air-guiding portions, wherein the first air-guiding portion includes a first guiding face at the air inlet, wherein the second air-guiding portion includes a second guiding face at the air inlet, wherein the first guiding face intersects the inner peripheral face of the lateral wall by a first included angle, wherein the first included angle is smaller than 180 degrees, and wherein a distance between the first and second guiding faces is gradually reduced from the air inlet towards a center of the fan frame; an impeller rotatably coupled with the shaft seat of the fan frame; and a cover plate coupled with a top edge of the lateral wall.
 2. The advection fan as claimed in claim 1, wherein the second guiding face intersects the inner peripheral face of the lateral wall by a second included angle, and wherein the second included angle is smaller than 180 degrees.
 3. The advection fan as claimed in claim 2, wherein the first air-guiding portion comprises a first air-guiding face at the air outlet, and wherein the second air-guiding portion comprises a second air-guiding face at the air outlet.
 4. The advection fan as claimed in claim 3, wherein the first and second air-guiding faces are parallel to each other.
 5. The advection fan as claimed in claim 3, wherein a distance between the first and second air-guiding faces is gradually reduced from the air outlet towards the center of the fan frame.
 6. The advection fan as claimed in claim 1, wherein the first air-guiding portion has a first angular end at the air inlet, wherein the first air-guiding portion has a second angular end at the air outlet, wherein the second air-guiding portion has a third angular end at the air inlet, wherein the second air-guiding portion has a fourth angular end at the air outlet, wherein a first boundary line extends through the first angular end of the first air-guiding portion and the third angular end of the second air-guiding portion, wherein a second boundary line extends through the second angular end of the first air-guiding portion and the fourth angular end of the second air-guiding portion, wherein a reference line extends through the center of the shaft seat and the air outlet, wherein the reference line extends perpendicular to the second boundary line, wherein the lateral wall further comprises an air-separating portion, wherein the air-separating portion is coupled with the second air-guiding portion and extends inwards in a radial direction, and wherein the air-separating portion is located between the reference line and the first boundary line.
 7. The advection fan as claimed in claim 6, wherein a first auxiliary line extends through the center of the shaft seat and the first angular end of the first air-guiding portion, and wherein the first auxiliary line intersects the reference line by a third included angle.
 8. The advection fan as claimed in claim 7, wherein the third included angle is between 35 degrees and 55 degrees.
 9. The advection fan as claimed in claim 7, wherein the third included angle is 35 degrees.
 10. The advection fan as claimed in claim 7, wherein the third included angle is 45 degrees.
 11. The advection fan as claimed in claim 7, wherein the third included angle is 55 degrees.
 12. The advection fan as claimed in claim 6, wherein a second auxiliary line extends through the center of the shaft seat and the fourth angular end of the second air-guiding portion, and wherein the second auxiliary line intersects the reference line by a fourth included angle.
 13. The advection fan as claimed in claim 12, wherein the fourth included angle is between 15 degrees and 35 degrees.
 14. The advection fan as claimed in claim 12, wherein the fourth included angle is 15 degrees.
 15. The advection fan as claimed in claim 12, wherein the fourth included angle is 25 degrees.
 16. The advection fan as claimed in claim 12, wherein the fourth included angle is 35 degrees.
 17. The advection fan as claimed in claim 6, wherein the first and second guiding faces resemble the shape of “/ \”.
 18. A fan frame of an advection fan comprising: a bottom plate provided with a shaft seat; and a lateral wall surrounding the shaft seat and having a first air-guiding portion and a second air-guiding portion, wherein the first air-guiding portion has first and second ends, wherein the second air-guiding portion has first and second ends, wherein an air inlet is formed between the first ends of the first and second air-guiding portions, wherein an air outlet is formed between the second ends of the first and second air-guiding portions, wherein the first air-guiding portion includes a first guiding face at the air inlet, wherein the second air-guiding portion includes a second guiding face at the air inlet, wherein the first guiding face intersects the inner peripheral face of the lateral wall by a first included angle, wherein the first included angle is smaller than 180 degrees, and wherein a distance between the first and second guiding faces is gradually reduced from the air inlet towards a center of the fan frame.
 19. The fan frame of the advection fan as claimed in claim 18, wherein the second guiding face intersects the inner peripheral face of the lateral wall by a second included angle, and wherein the second included angle is smaller than 180 degrees.
 20. The fan frame of the advection fan as claimed in claim 19, wherein the first air-guiding portion comprises a first air-guiding face at the air outlet, and wherein the second air-guiding portion comprises a second air-guiding face at the air outlet.
 21. The fan frame of the advection fan as claimed in claim 20, wherein the first and second air-guiding faces are parallel to each other.
 22. The fan frame of the advection fan as claimed in claim 20, wherein a distance between the first and second air-guiding faces is gradually reduced from the air outlet towards the center of the fan frame.
 23. The fan frame of the advection fan as claimed in claim 18, wherein the first air-guiding portion has a first angular end at the air inlet, wherein the first air-guiding portion has a second angular end at the air outlet, wherein the second air-guiding portion has a third angular end at the air inlet, wherein the second air-guiding portion has a fourth angular end at the air outlet, wherein a first boundary line extends through the first angular end of the first air-guiding portion and the third angular end of the second air-guiding portion, wherein a second boundary line extends through the second angular end of the first air-guiding portion and the fourth angular end of the second air-guiding portion, wherein a reference line extends through the center of the shaft seat and the air outlet, wherein the reference line extends perpendicular to the second boundary line, wherein the lateral wall further comprises an air-separating portion, wherein the air-separating portion is coupled with the second air-guiding portion and extends inwards in a radial direction, and wherein the air-separating portion is located between the reference line and the first boundary line.
 24. The fan frame of the advection fan as claimed in claim 23, wherein a first auxiliary line extends through the center of the shaft seat and the first angular end of the first air-guiding portion, and wherein the first auxiliary line intersects the reference line by a third included angle.
 25. The fan frame of the advection fan as claimed in claim 24, wherein the third included angle is between 35 degrees and 55 degrees.
 26. The fan frame of the advection fan as claimed in claim 24, wherein the third included angle is 35 degrees.
 27. The fan frame of the advection fan as claimed in claim 24, wherein the third included angle is 45 degrees.
 28. The fan frame of the advection fan as claimed in claim 24, wherein the third included angle is 55 degrees.
 29. The fan frame of the advection fan as claimed in claim 23, wherein a second auxiliary line extends through the center of the shaft seat and the fourth angular end of the second air-guiding portion, and wherein the second auxiliary line intersects the reference line by a fourth included angle.
 30. The fan frame of the advection fan as claimed in claim 29, wherein the fourth included angle is between 15 degrees and 35 degrees.
 31. The fan frame of the advection fan as claimed in claim 29, wherein the fourth included angle is 15 degrees.
 32. The fan frame of the advection fan as claimed in claim 29, wherein the fourth included angle is 25 degrees.
 33. The fan frame of the advection fan as claimed in claim 29, wherein the fourth included angle is 35 degrees. 